[rcrapps]

Originally Posted by Scallywag

There is about 12 inches of shaft log tube inside the hull, but the weld is "built up" a bit under the tube leaving about 8 inches. Enough for a bunch of hose clamps.

Then that should be plenty. I with draw my concern on that then.

[rgsuspsa]

Originally Posted by Marmot

Just read today's posts ... geez, that really is an ugly bunch of welds! It looks like something I might have done while trying out a new spool gun.

That soot is from using 5xxx series wire and dragging the torch rather than pushing it. Some of that soot will be included in the weld itself and lead to porosity. A little bit of soot is all but unavoidable because it is from the magnesium in the metal. If you use a wire brush on a die grinder it will actually combust and make a neat looking expanding ring of orange that looks like a grass fire as seen from the air.

I guess if you slobber enough metal on something you might get structural support but usually a weld is about as good as it looks and those look like crap, not matter what the locals say about it.

The weld photographs depict weld regions which appear sound, and regions which appear quite poor. For any given weld joint the entire weld, both internal and external to the hull must be sound. I believe these welds are going to be problematic within a period of time which will be quite short of their intended service life. Either deal with them now, or someone will be dealing with them in the not too distant future.

Ron Sparks

[Scallywag]

Originally Posted by rgsuspsa

The weld photographs depict weld regions which appear sound, and regions which appear quite poor. For any given weld joint the entire weld, both internal and external to the hull must be sound. I believe these welds are going to be problematic within a period of time which will be quite short of their intended service life. Either deal with them now, or someone will be dealing with them in the not too distant future.

Ron Sparks

Thanks for chiming in Ron. The collective knowledge of this forum is amazing. I've done quite a bit of reading over the past week regarding welding and have learned quite a bit. As always, I still have tons to learn.

The in the Weld Defects section of the MIG handbook it refers to porosity. As I understand it, the soot is indicative of porosity usually caused by unclean material or inadequate shield gas. With MIG welding it is often caused by "dragging" the weld instead of "pushing" it. Especially with 5000 series wire. The porosity may or may not be inside the joint, but the only way to tell is by x-ray. In practice, excessive sooting is a good indicator of porosity.

Let me know if I have that info right.

A lot of this has been stated in different ways by forum members. What amazes me is the "professionals" haven't mentioned this even if they have nothing to lose by saying "that there weld is a pile of crap!"

I appreciate everybody's input and hopefully I can return the information overload I'm receiving to the next new member.

Starboard side is removed and ready for welding. The outside weld is the most concerning to me. The inside hull welds seem adequate. As was stated by somebody else "grind it out and do it again!"

[Savasa]

Scallywag,
I'm no welder but there is NO penetration in the tube in the last pictures you posted.
Peter

[Scallywag]

Originally Posted by Savasa

Scallywag,
I'm no welder but there is NO penetration in the tube in the last pictures you posted.
Peter

You mean this one?

http://www.yachtforums.com/forums/at...n-img_2599-jpg

[Bill106]

Originally Posted by Scallywag

Bills pics look absolutely excellent. Was that accomplished with MIG? In a shop or a yard? Upside down? Wind conditions?

Turns out a guy at the yard that I've shot the breeze with just about every day for the last three weeks welds. He just about mirrored exactly what the other welder said.

I know close to nothing about welding, but it seems like everybody here concurs that if it isn't a roll of dimes it's a bad weld and if there is soot then the weld is cold and penetration is bad. Every professional I've spoke to says otherwise when they have nothing to gain either way?

I guess keep asking different professionals for consultation until I find one that agrees?

That was definitely MIG and inside the shop with no wind to blow the gas away from the weld. Some were inverted and just about any orientation but I couldn't tell a difference. I am by no means an expert in welding but those guys we hired are the absolute best I've ever had the pleasure of working with. There is a huge difference in tower stick welding (TIG) and plate welding and I've got a renowned tower builder across the street but when these guys were at work they came over and stood slack jawed at the artistry being created. One of the guys had over 25 years of aluminum hull building experience but his apprentice was nearly as good after only tweo years.

The second set of pics you posted up looks much better to my untrained eye
and mainly because the start/stops looked properly done. One thing those OA/SWS guys taught us was the proper way to do that was to grind back into the end of the weld before restarting.

Be leery of soliciting advice from general purpose welders. I've discovered there is a specialty within a specialty when it comes to proper metal hull building techniques.

[Marmot]

Originally Posted by Scallywag

... it seems like everybody here concurs that if it isn't a roll of dimes it's a bad weld and if there is soot then the weld is cold and penetration is bad. Every professional I've spoke to says otherwise when they have nothing to gain either way?

Try the professionals at Miller, they might not agree with the ones you have spoken to. Or, if you like, go take a look at an aluminum boat built by Derecktor or any another builder with a reputation for quality aluminum boat building.

AL MIG welds from Miller:

[ArielM]

I am not a professional welder but i enjoy metal fabrication on the side and the welds done on this repair are not adequate at all.

First of all a repair like this should be TIG welded by a professional. Due to the fact that this hull have been sitting in salt water for this long, there is a lot of oxidation and contamination in the base metal. Welding alum. is very techincal and should only be done by a professional. There is also no cleaning action around the foot of the welds. weld is also too cold. You should also check what filler metal the welder used. 5356 (or 5xxx series) is marine grade alum.

Lack of "stack of dimes" DOES NOT mean it is a bad weld. the stack of dimes comes when you add filler metal to the weld puddle. If the welder feeds filler metal at a faster pace or lays wire then the ripples come much closer together and you can lose that affect without sacrificing the joint.

I wouldn't trust those welds one bit.

On a side note cleaning the alum with Stainless Steel brush is common practice. (That brush should not be used on any other metal though)

I've seen better welds but I'm not a weld expert, however we have had recent experience on bearings installed in Al ships, there had been problems with previous shaft bearings where corrosion was seen between the bearing and the bearing carrier/tube/strut. This caused some bore closure and tight running which gave shaft and bearing wear. These were composites that were freeze fit so no metal to metal issues just pockets of salt water. These were changed for clearance fit fully composite phenolic bearings these from Australia were also resistant to marine growth, so far (three years) so good, very low wear rates and no shaft damage or corossion. So epoxy bedding to manufacturers clearances seems to work well.